Gas pump for outboard motor



July 26, 1955 D. A. ARMSTRONG Er Al. 2,713,858

GAS PUMP FOR OUTBOARD MOTOR Filed April 2l, 1950 K 2 Sheets-Sheet l FIE z 0 E 'GTE V /z /l l/ile z/ .zo il I I l *l 7'0 caksunfroe O z3 l fz wim a @j /'Roue/IsT/m/K .l I Q l :Il O I E+-Er' E ,n

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GAS PUMP FOR oUTBoARD MOTOR Filed April 21, 195o 2 sheets-sheet 2 States ratented July 26, 1955 GAS PUB/IP FOR UTBARD MOTOR Daniel A. Armstrong, Walter J. Raleigh, and Allan G. Scott, Minneapolis, Minn., assignors to Scott-Atwater Manufacturing Co. Inc., Minneapolis, Minn., a corporation of Minnesota Application April 21, 1950, Serial No. 157,232 4 Claims. (Cl. 123-139) This invention relates to a two cycle motor such as it is a further object of the invention to provide a pump comprising a chamber adjacent the crank case chamber and communicating therewith, a passage adjacent said iirst mentioned chamber and communicating therewith, a diaphragm extending across said Iirst mentioned chamber, and oppositely disposed check valves in said passage at opposite sides of the point of communication of said passage with said rst mentioned chamber.

It is another object of the invention to provide such a structure as set forth in the preceding paragraph, with an additional chamber at one side of one 0f said check valves through which valve liquid is forced by pressure in said crank chamber, said additional chamber communicating with said first mentioned passage and communicating with the atmosphere, and having therein a yielding means between said passage and the atmosphere for resisting the passage of air therethrough.

It is also an object of the invention to provide a simple pump for a two cycle motor having a crank case chamber, a passage disposed adjacent said chamber, a second chamber between said passage and crank case chamber and communicating with said crank case chamber, a second passage extending between said rst mentioned passage and chamber, a diaphragm extending across said second chamber, oppositely disposed check valves at opposite sides of said second passage, a conduit leading from said iirst mentioned passage at the remote side of one of said valves to the carburetor of said motor, and a second conduit leading from the remote side of the other valve to a liquid supply for said motor.

It is still further an object of the invention to provide a simple and eicient pump structure for a two cycle motor having two cylinders and two crank case chambers, said structure comprising a passage adjacent said crank case chambers, a pair of chambers disposed respectively between said crank case chambers and said passage and communicating respectively with said crank case chambers, spaced passages leading from said rst mentioned passage to said last mentioned chambers respectively, a check valve in said lirst mentioned passage between said last mentioned passages, and oppositely disposed check Valves at the remote sides of said last mentioned passages.

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:

Fig. 1 is a partial view in side elevation of a portion of a crank case of an outboard motor;

Fig. 2 is a view in side elevation as seen from the right of Fig. 1;

Fig. 3 is a vertical section taken substantially on line 3 3 of Fig. 1, as indicated by the arrows;

Fig. 4 is a view in side elevation as seen from the left of Fig. l along line 4 4; and

Fig. 5 is a view generally similar to Fig. 3 showing a two cylinder crank case and pump structure.

Referring to the drawings, particularly Figs. l to 4, a portion 10 of the crank case of a two cycle motor is shown, which crank case has therein a crank case chamber illu. As is well known, in a two cycle motor the fuel charge is compressed in the crank case chamber and then delivered to the cylinder. Crank case 10a is provided at one side with a iat surface 10b. A member 11a having a iiat surface is secured with its flat surface against the flat surface 10b by a plurality of bolts 12. Member 11 has a passage 11a therethrough shown as closed at either end. While various closures could be used, in the embodiment of the invention illustrated passage 11a is provided at its ends with shallow counterbores 11b and circular disks 13 are pressed into said counterbores. Disposed between passage 11a and the crank case chamber 10a is a chamber 14. Chamber 14 comprises two oppositely disposed portions 14a and 14h each shown as in the form of a segment of a sphere with their larger sides adjacent each other. A flexible and/or resilient diaphragm 15 is disposed between members 11 and 10 and clamped therebetween, said diaphragm extending across chamber 14 substantially at its central and widest portion and between passage 11a and crank case chamber lila. While said diaphragm may be made of various materials, in practice it has been made of neoprene, or nylon fabric impregnated with neoprene. A passage 10c connects chamber 14 with crank case chamber 10a and a passage 11C connects passage 11a and chamber 14 at the side of diaphragm 15 opposite passage 10c. A check valve 17 is disposed in passage 11a at one side of passage 11e and is arranged to permit the passage of liquid upwardly in passage 11a, as seen in Fig. 3, and to prevent the passage of liquid downwardly, as seen in Fig. 3. Another check valve 18 is disposed in passage 11a at the opposite side of passage 11C from Valve 17, and check Valve 18 prevents the passage of liquid downwardly in passage 11a, as seen in Fig. 3, but permits the passage of liquid upwardly therein, as seen in Fig. 3. Member 11 has spaced bosses 11d and 11e having therein passages 11f and 11g, which latter passages communicate with passage 11a at the remote sides of the Valves 17 and 18 respectively. A conduit 2) is connected to passage 11f by a suitable connection 21 and will communicate with the carburetor of the motor. Another conduit 22 is connected to passage 11g by a suitable connection 23 and will communicate with the liquid fuel supply or gas tank of the motor.

Beyond check valve 17 a comparatively small chamber 10d is provided which communicates through a passage 19e with the atmosphere and communicates through another passage 10J with passage 11a above valve 17, as seen in Fig. 3. Diaphragm 15 which is held between the fiat surfaces of members 1i) and 11 extends through chamber 10d between passages 10e and lllf. While any suitable type of check Valve could be used for the valves 17 and 18, in the embodiment of the invention illustrated these valves comprise a cylindrical casing 17a or 18a having an end with an opening 17h or 18h therethrough. This opening forms an annular flange at said end on which rests a small flat disk 17C or 18C. A plurality of circumferentially spaced inwardly extending prongs 17d and 18d are formed on the casings 17a and passage of liquid therein.

18a some distance above openings 17b and 1817 to prevent excessive movement of the disks 17e` and 18e.

In operation, when the fuel charge is compressed in crank case chamber a the pressure therein will flex diaphragm and move it to the left, as seen in Fig. 3. This will create pressure in passage 11a between valves 17 and 1S and valve 17 will be opened by a passage of air or liquid therethrough due to said pressure. When said pressure is relieved a pressure below atmospheric pressure is produced in crank case chamber 10a, diaphragm 15 will be flexed to the right as seen in Fig. 3, and a suction or reduced pressure will be formed between valves 17 and 18 in passage 11a. This will hold valve 17 closed and valve 18 will be opened. Liquid from the liquid supply or gas tank will be drawn into passage 11a through conduit 22. This liquid will pass into passage 11a between valves 17 and 13. When pressure again occurs in crank case chamber 10a, diaphragm 15 will be flexed to the right, as seen in Fig. 3, and will force liquid from between the valves 17 and 1S through the valve 17. lt will thus be seen that with each period of pressure in crank case chamber tla liquid will be forced from passage 11a between valves 17 and 18, through valve 17, and when a reduced pressure or suction occurs in chamber 10a, liquid will be drawn into passage 11a through valve 18. The liquid will pass to conduit 2) and be supplied to the carburetor. When liquid is forced upward in passage 11a above valve 17, pressure is exerted against the diaphragm in chamber 10d. Said diaphragm will yield slightly and thus forms a yielding means resisting said pressure. Chamber 10d thus forms an equalizing chamber. it has been found in practice that the provision of chamber 1bn.' with its yielding means or diaphragm causes a much steadier and unifor operation of the pump giving a much smoother discharge of liquid. A very simple and eicient pump is thus provided which is actuated by the pressure changes in the crank case chamber or a communicating chamber of the motor.

ln Fig. 5 a portion of a crank case chamber 30 is shown having two crank case chambers a and 30]) respectively. Member 30 has a at surface 30am, and a member 31 having a flat surface 31a is provided the same having a passage 31b therethrough. Members 30 and 31 each have a pair of semi-spherical recesses therein which have their larger sides adjacent and in alinement when members 30 and 31 are connected to form the chambers 32 and 33 respectively. Chambers 32 and 33 communicate respectively with chambers 30a and 30h through passages 30C and 30d. Said chambers 32 and 33 also communicate with passage 31b through the respective passages 31C and 31d. A tlexible resilient diaphragm 35 is disposed between the flat surfaces of members 30 and 31 and this diaphragm extends across the center and widest part of each chamber 32 and 33. lt will be noted that passages 31C and 31d are at one side of diaphragm 35 and that passages 30e and 30d are at the opposite side of said diaphragm. A check valve 36 is disposed in passage 31b and disposed so as to permit the upward passage of liquid in passage 31h but to prevent downward Check valves 37 and 38 are disposed in passage 31h at the remote sides of passages 31C and 31d respectively. Check valve 37 permits upward passage of liquid but will prevent downward passage of liquid, as seen in Fig. 5. Check valve 38 will also permit upward passage of liquid but will prevent downward passage of liquid, as seen in Fig. 5. A suitable coupling 40 is secured to the upper end of passage 31h and will have connected thereto a conduit 41 which will extend to the carburetor of the motor. Another coupling 42 is connected to the lower end of passage 311; and has connected thereto a conduit or hose 43 secured by a clamping ring 44, which conduit 43 will extend to the fuel tank or liquid fuel supply. At the remote sides of chambers 32 and 33 are smaller chambers 46 and 47 formed partly in member 36 and partly in member 31. Chamber 46 in member 30 communicates with the atmcspherc through a passage 30e. Chamber 47 in member 39 communicates withv the atmosphere through a passage 30j. Diaphragm 35 extends across passages 46 and 47. Passage 46 communicates with passage 31b through a passage 31e and chamber 47 communicates with passage 31b through a passage 31f. It will be noted that passages 31e and 31]c are at one side of diaphragm 35 and that passages 30e and 30j are at the opposite side of said diaphragm.

The crank case chamber 3G is used in a twin motor which has two cylinders. The cylinders are arranged to flre alternately and the gaseous charge of fuel is cornf pressed in chambers 30a and 30h at alternate periods.

When compression occurs in chamber 30a, diaphragm 35 will be pushed toward passage 31h and liquid in passage 31b between valves 37 and 36 will be forced upward through valve 37. When said compression ceases in chamber 30a, a reduced pressure or suction occurs in chamber 30a and diaphragm 35 will be flexed to the right, as seen in Fig. 5, and liquid will be drawn upwardly through valve 36 into the space between valves 37 and 36. `vii/hen compression ceases in chamber 30a, compression will take place in chamber 30h and diaphragm 35 in chamber 33 will be pushed toward passage 31b and liquid in passage 31h between valves 36 and 38 will be forced upwardly through valve 36. When reduced pressure occurs in chamber 30h, diaphragm 35 will be flexed away from passage 31h and liquid will be drawn upwardly through valve 38 into the space between valves 36 and 38, valve 36 at this time being closed. The diaphragms of chambers 32 and 33 are thus operated alternately and liquid is alternately forced upward through passage 31b. This liquid will be drawn through the conduit 43 from the gas tank or fuel supply and will be forced through conduit 41 to the carburetor. Passages 46 and 47 are provided as equalizing passages. When the liquid is forced upwardly there is some pressure exerted against the diaphragm in chambers 46 and 47 rcspectively. There is usually a check valve (not shown) in the line below coupling 42. The diaphragm will yield slightly and forms a yielding means resisting the pressure thereagainst. It is found that by providing chamber 46 with the diaphragm therein that a much steadier and regular operation is had and a much smoother discharge of liquid obtained. Chamber 47 and the diaphragm therein relieves the pulsations of liquid in conduit 42, preventing pounding and giving a smoother operation.

From the above description it will be seen that we have provided a very simple and eicient pumping device for a two cycle motor. The pumping is effected by the changes of pressure in a chamber or chambers of the motor and the pulsations of the diaphragms are synchronous with the speed of the motor. The fuel is thus supplied in accordance with the demands of the motor. The structure is simple and inexpensive and the parts are easily assembled. The device has been amply demonstrated in actual practice, found to be very successful and efficient and is being commercially made.

It will of course be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

l. A two cycle motor having two cylinders and two chambers in which a change of pressure occurs having in combination, a passage adjacent said chambers, diaphragm chambers adjacent said first mentioned chambers respectively and communicating respectively therewith, diaphragms extending across said diaphragm chambers respectively, said diaphragm chambers each having opposed wails at the opposite sides of said diaphragms respectively, passages leading from said first mentioned passage to said diaphragm chambers respectively at the sides thereof opposite said first mentioned chambers, and three check valves including a check valve in said first mentioned passage between said last mentioned passages, and check valves disposed in said first mentioned passage beyond said last mentioned passages respectively preventing passage of liquid in opposite directions.

2. A two cycle motor having two cylinders having in combination, a crank case member having therein two crank case chambers, a passage adjacent said chambers, diaphragm chambers adjacent said crank case chambers respectively and communicating respectively therewith, said member being divided into two parts along a plane passing substantially centrally through said diapl'iragmv chambers, a diaphragm extending across said diaphragm chambers respectively, disposed and held between said two parts, passages leading from said first mentioned passage to said diaphragm chambers respectively at the sides thereof opposite said crank case chambers, a check valve in said first mentioned passage between said last mentioned passages, and check valves disposed in said first mentioned passages beyond said last mentioned passages respectively preventing passage of liquid in opposite directions.

3. A crank case member having a at side, said member having therein two crank case chambers having axes disposed perpendicular to said flat side, said member having spaced chambers therein at said fiat side each in the form of a segment of a sphere each having its central axis perpendicular to said side, passages respectively connecting said spaced chambers and first mentioned chambers, the axes of said passages being coincident with the axes of said chambers respectively, a second member having a flat side with spaced chambers therein similar to said spaced chambers and aligned therewith, a flexible diaphragm between and engaging said fiat sides of said members and thus extending between said spaced chambers, said second member having a second passage therein e:r4 tending parallel to said fiat sides, third passages extending from said spaced chambers respectively to said second passage, three check valves in said second passage, one being disposed between said spaced chambers and the others being disposed beyond said third passages respe,

tively, a conduit connected to one end of said second passage and adapted to connect said second passage to a carburetor, and a second conduit connected to the other end of said second passage and adapted to connect said second passage to a supply of fuel.

4. A crank case member having a flat side, said member having therein two spaced crank case chambers and two spaced second chambers, the latter opening at said fiat side, first and second passages respectively connecting said crank case chambers and said spaced second chambers, a second member having a fiat side, said second member having spaced third chambers opening at its flat side aligned with said spaced second chambers respectively, a diaphragm extending between said spaced second and third chambers and engaged by said fiat sides, said second member having a third passage extending substantially parailel togsaid fiat sides, a pair of fourth passages respectively connecting said spaced third chambers and said third passage, three check valves in said third passage, one being disposed between said fourth passages and the other two being disposed beyond said fourth passages respectively and preventing fiow of uid in opposite directions respectively, a fourth chamber in said second member beyond one of said other two valves, a fifth passage connecting said fourth chamber to said third passage, a fifth chamber in said first mentioned member beyond said one of said other two valves, said diaphragm passing between said fourth and fifth chambers, a sixth passage connecting said fifth chamber with the atmosphere, a conduit connected to one end of said third passage and adapted to be connected to a carburetor and a second conduit connected to the other end of said third passage and adapted to be connected to a source of fuel supply.

References Cited in the file of this patent UNiTED STATES PATENTS 11,559 Pease Aug. 22, 1854 434,171 Baldwin Aug. 12, 1890 1,022,803 Troutt Apr. 9, 1912 1,525,865 Johanson Feb. l0, 1925 2,203,464 Harry `lune 4, 1940 FOREIGN PATENTS 120,071 Great Britain Oct. 16. 1917 

